package com.saber.king.utils;

import com.alibaba.druid.util.StringUtils;
import com.saber.king.constants.Constant;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;

import javax.servlet.http.HttpServletRequest;

/**
 * @author Saber污妖王
 * TODO: 获取 IP 地址
 * @version 0.0.1
 * @editor Saber污妖王
 * @project company-frame
 * @date 2020/3/25
 * @package com.saber.king.utils
 */
public class IpUtils {

    private static final Logger logger = LoggerFactory.getLogger(IpUtils.class);

    public static final int IP_LENGTH = 15;

    /**
     * 获取IP地址
     * <p>
     * 使用Nginx等反向代理软件， 则不能通过request.getRemoteAddr()获取IP地址
     * 如果使用了多级反向代理的话，X-Forwarded-For的值并不止一个，而是一串IP地址，X-Forwarded-For中第一个非unknown的有效IP字符串，则为真实IP地址
     */
    public static String getIpAddr(HttpServletRequest request) {
        String ip = null;
        try {
            ip = request.getHeader("x-forwarded-for");
            if (StringUtils.isEmpty(ip) || Constant.UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("Proxy-Client-IP");
            }
            if (StringUtils.isEmpty(ip) || ip.length() == 0 || Constant.UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("WL-Proxy-Client-IP");
            }
            if (StringUtils.isEmpty(ip) || Constant.UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_CLIENT_IP");
            }
            if (StringUtils.isEmpty(ip) || Constant.UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getHeader("HTTP_X_FORWARDED_FOR");
            }
            if (StringUtils.isEmpty(ip) || Constant.UNKNOWN.equalsIgnoreCase(ip)) {
                ip = request.getRemoteAddr();
            }
        } catch (Exception e) {
            logger.error("IPUtils ERROR ", e);
        }

        // 使用代理，则获取第一个IP地址
        if (!StringUtils.isEmpty(ip) && ip.length() > IP_LENGTH) {
            if (ip.indexOf(Constant.COMMA_DELIMITER) > 0) {
                ip = ip.substring(0, ip.indexOf(","));
            }
        }

        return ip;
    }

}
